Hello everyone,
Greetings today!
Today we'll go over how to remove duplicate elements from a list, which is frequently needed during development.
Two approaches are provided below.
- Making Use of HashSet
- Using Java 8's distinct() method
Using HashSet
package com.demo; import java.util.ArrayList; import java.util.HashSet; import java.util.List; public class Test { public static void main(String[] args) { List<String> fruits=new ArrayList<String>(); fruits.add("Apple"); fruits.add("Mango"); fruits.add("Apple"); fruits.add("Grapes"); System.out.println("List with duplicate fruits ::" + fruits); List<String> uniqueFruits = new ArrayList<>(new HashSet<>(fruits)); System.out.println("unique fruits are " + uniqueFruits); } }
Because HashSet does not allow duplicates, we used HashSet to remove the duplicate element in the preceding example.
O/P
List with duplicate fruits::[Apple, Mango, Apple, Grapes]
unique fruits are [Apple, Grapes, Mango]
Using Java 8's distinct() method - the distinct method will automatically remove the duplicate element from the input stream and then collect the stream back to the list.
package com.demo; import java.util.ArrayList; import java.util.List; import java.util.stream.Collectors; public class Test { public static void main(String[] args) { List<String> fruits=new ArrayList<String>(); fruits.add("Apple"); fruits.add("Mango"); fruits.add("Apple"); fruits.add("Grapes"); System.out.println("List with duplicate fruits ::"+fruits); List<String> distinctFruits= fruits.stream().distinct() .collect(Collectors.toList()); System.out.println("Distinct fruits using java 8 ::" +distinctFruits); } }
O/P
List with duplicate fruits::[Apple, Mango, Apple, Grapes]
Distinct fruits using java 8::[Apple, Mango, Grapes]
Thanks
Enjoy your learning!
Another post you can refer to is
For spring refer to Spring Tutorial
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